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Accesing the corresponding cells on either side of a wall - wall shadow zone.

It is sometimes necessary to reference the cells on either side of the wall/wall-shadow zone. Mostly to get the temperature difference. But F_C1 does not work here. Instead, there are a couple of macros that work here -Thread *t_shadow=THREAD_SHADOW(t);face_t f_shadow=F_SHADOW(f,t);These are defined in "mem.h".The resolution below contains a UDF that uses these macors to compute the temperature difference between a solid cell and fluid cell separated by a wall - wall shadow zone.#include "udf.h"#define wall_id 11 /*change this number according to your case */